PSD file size bug

[minkop70380424]

There is serious issue with the PSD file size.

How to reproduce:

1. Create blank document 500x500x72 pixels with one white layer - save - PSD size 162kb

2. Insert 3840x2160 image and transform it down to fit 500x500 - save - PSD Size 10mb

(So problem n1, transformed 4k image to 500x500px should not be 10mb file size)

3. Delete the layer contains the 4k image - save - PSD Size 10mb

So even after the image is deleted and i have left only one white layer the file size is still big, this dosn't make any sense.

[Test Screen Name]

In case anyone should be following my discussion of PSD file sizes

(to emphasise, I don't think that's the key point here)... I did

some tests with Photoshop 2017.

Image size: 512 x 512. Raw image data size (in memory) 768K (100%).

Filled with white (single layer). PSD size 32K (4%).

Filled with gradients (single layer). PSD size 787K (102%).

  Same gradient file as a PNG. PNG size 104K (13%).

Add one white layer behind (invisible). PSD size 1583K  (206%).

  Same file as PNG. PNG size 117K (15%).

Commentary: this shows (1) that PSD files may not compress at all

(2) once you have layers you have the composite view as well as

each layer (3) the exact same image may produce different PNG sizes

too.

[Soundgarden]

Are we're talking about RAM memory size or file size once saved? I have been told by Adobe techs, that Photoshop will eat memory on purpose - to reserve it for when it's needed. There have been numerous discussions on the inflated RAM in the Photoshop community.

According to Adobe, if you open Photoshop - memory shows 500mb.  You open a really large file, memory goes to 4gb. You then close that large file and have zero files open in Photoshop - memory stays at 4gb. Apparently Photoshop will always retain/reserve RAM that it uses and never release it (even with purges) until you close Photoshop.

[Test Screen Name]

In my example, 768K is the size of a single layer in memory (I write that as 100%).

Once there are 2 layers there will be 3 copies (layer+layer+composite)

But then there is the history. 100 steps in the history? Has to go somewhere. Will start in memory, and then run to the scratch disk. 100 steps, 2 layers is perhaps 200 megabytes.

But some people have 100 layers. Maybe 20 GB.

But this is a very small 512 x 512 image. It adds up very fast.